Sound amplifier



' Aug. 16, 1927.

G. C. WILHELM] SOUND AMPLIFIER Filed Junge 9. 192s 3 Sheets-Sheetl Aug. 16, 1.927. 1,639,3594

G. C. WILHELMI scum: AMPLIFIER."

YFiled June 1926 s sheets-Shana Aug- 16 1927' G. c. WILHELMI SOUND AMPLIFIER vFiled June 9, 1926 5 Sheets-Sheet 3 ',mma" 'I gf Y erably of' wood construction providing rich Patented Aug.y 16, 1927.

UNITED STATES eUs'rAvE'c. WILHELMI, or CLEVELAND, omo.

souivn AMPLIFIER.`

This invention relates to new and useful improvements in sound amplifiers and more phone sound waves, 'providing a simple com-` pact, attractive structure preferably of wood embodying in combination with sound boxes a radiophone communicating with an elongated offset tortuous sound passage of gradually expanding cross sectional areahaving a concentric outlet emanating theI spirally directed sound waves forwardly and'radially providing maximum and eiiicient acoustic range of the amplifier. y i

Other objects and features of the invention will behereinafter pointed out and described. 4

In the drawingst- 'f Fig. 1` is a front elevation of the amplifier.. u

' Fig. 2 is asimilar view with the front 'wall and mouthpiece vremoved'.

' Fig. 3 isa rear" elevation with the'rear wall removed. Y Fig. 4 is a detail view ofl the tone regulating fillerstripremoved f Fig; "5' is an edge view'tl`1ereof.` Y Fig. 6 isa sectionalview on line 6-'6 lof Fig. 1. i

7 tisa section, on linev of Fig. 2, with thefront'wa'll and mouthpiece applied. Fig.f8` isa section Online 8-f8`of Figf2. v9 is asecti'on on line 9"-.9 of

'Referring specifically tothe drawings,` the amplifier apart "from 'the .radiophone is prelfness'and4 clarity of tone and is supported,on a baseA 5 removably secured ,byA screwsyto the curved side legs 6, front wall 17' and back Awal18 supporting between them the cylindrical amplifierbody 9 comprisingannular ringslO and v12 and amouthpiece 14 having aV concentric bellfshaped outlet v15 flaring forwardly lvand`V outwardly to -'the front vthrough an' opening 16`in front wall 7. The inner restricted lend 17 of outlet 15 opening through the rear of mouthpiece 14 is concentrically disposed relative to" the rings 1() and 12.` y y The joint 18 between mouthpiece'14 and ring 12 is offset as at .19 and an internal groove 21 is provided at joint 2O between rings 10 and 12`for receiving a disc-shaped partition 22. v l

As shown 'in Figs. 3 and 61a convolute or spiral-shaped sound passage wall indicated generallyl at 23 comprises an annular inner sidewall surface 24 concentricY with the center vof rings 10 and 12, and an outer side wall surface 25 of one convolution convolute with the center of rings 10'and 12. The ends of the convolute wall 25 are positioned at the bottom thereof below the-'center of the convolute, the end indicated at 26 having the larger radius and the end indicated at 27 having the shorter radius. `As viewed in 3 an extension wall 28' is providedhaving its lower and upper sides 29 and 30 extending substantially horizontally to the left from the convolution wall 'ends 26 and 27 respectively to the inner side 11 of ring 10. The convolute wall 23 and extension 28 are suitably secured to partition `22 and'eXtend against rear wall 8 providing a sound box 311 between the annular wall partition 22 and rear wall 8.

`Aefilling strip 32 of tapering' cross sec- ,tionalr area having` an outer face or wall 33 is suitably secured to partition 22l .betweenl ring'wall 11, convolute wall 25" and extension wall 29, havingthe thickerv end y34 po-` sitioned at the meeting point' of ring wall `11 andextension wall 29, andthe reduced end3`5 extending'approximatelyto the height of thering center.

' An opening. 36 is provided 'in partition 22 having its bottom edge 37 flush with exten sion top side 30, side edges 38 and39 flush with a portion of ring wall 11 and convolu'tel wall 25 and a horizontal top edge 40 spaced from the lower edgef37.

f A soundpassage k41 of gradually expand-y ing crosssectional area is formed by filler wall 33, `extension wall 2.9,'- ring wall 11, rear wall8, convolute 25 and partition opening 36, having the smaller cross sectional rarea thereofr at the end 34- of iillerstrip 32 and the larger cross sectional area at par-` tition opening 36.

A block 42, suitably secured between ring 10 and 12, side `6 and back wall 8, has an annular recessl 43 in its bottom side and is tapped as at 44 communicating withA an opening- 45 in the block which communicates throughv an opening 10( in ring 10 with 'the reduced end ofthe sound passage 41.

The screw threaded neck 47 of a radiophone or microphone 46 is threaded into tap 44, the recess 43 receiving the shoulder of the radiophone casing. The radiophone lead wires 43 may be led out of the rear Wall 8 and connected to the radio receiving set.

Referring to Fig. 2, a Wall indicated generally at 49 suitably secured to partition 22 and extending between the partition and mouthpiece 14, has a horizontal bottom Wall portion 50 flush with partition opening edge 40 and an intersecting Wall 51 convolute to the center of ring l2, having its opposite free end 52 extending in a substantially horizontal plane with the ring center. The portion of Wall 51 at partition opening 36 is flush with the opening edge 39. The end 52 of Wall 51 meets a sen'iicircular wall 53 concentric with ring 12 and lying flush with the lower half edge o'l the restricted outlet openingv 17. The Wall 53 is continued upwardly curving over the ring center as at 54 and tern'iinates against ring 12 as at An upper inclined Wall 56 'forming a chord with ring 12 together with partition Walls 22fand mouthpiece 14 provides a sound box 57. The partition opening 36, Wall 50, convolute wall 51, ring 12, partition 22, mouthpiece 14, Walls and 54 provide a sound passage of gradually expanding cross sectional area, enlarging from partition opening 36 to Walls 54, 53 and outlet 17.

lVlien the amplifier is connected to a radio receivingl set and operated, the sound Waves from the radiophone diaphragm pass through the casing neck 47, block opening 45, ring opening 10', sound passage 41, partition opening 36, and the front sound passage adjacent the Walls 51 and 54 and are discharged through outlet 15, the sound Waves enlarging in volume and tone and clarifying they pass through the gradually expanding cross sectional area of the continuous sound passage and pass the sounding Walls offthe sound boxes 31 and 57. The curved Walls 54 and 53 direct the sound Waves spirally through the flared outlet 15. l

The radiophone 46 may be attached centrally at the rear Wall S or at the bottom of ring 10 if desired with a suitable connect- .ing passage to the passage 41.

The tone of the ampliiier may be regulated or adjusted by varying the length and tapering thickness of the filler strip 33, providing a line tone of Widek range. The compact arrangement of the sound passage and sound boxes provide an extra long travel of the sound Waves Within a st-ructure occupying a ininiinun'i of' space. The sound passage may be lengthened by providing additional partitions and varyinO the cylinder diameter.

The outer parts of the amplifier may be constructed of suitable ivood to match any furniture. The partition 22, Walls 23, 28, 49, .filler strip 33 and block 47 are preferably of violin spruce, poplar, birch or like woods to impart clearness and neness of tone amplifying at the sound boxes.

The amplifier is adaptable foruse in connection with any type of sound producing o1' reproducing apparatus.

lVhile I have shownand described one enr bodiment of my invention, obviously various changes in the proportions and details of construction may be made Within the scope and spirit oit the appended claims.

I claim 1. A sound amplifier comprising a casing having front and rear convolute tapered sound passages in parallel planes, the larger end of the rear passage communicating with the smaller end ot' the front passage, the rear passage having a peripheral inlet and the front passage having an enlarged axial outlet.

2. A sound amplifier' comprising a casing having front and rear convolute tapered sound passages in parallel planes, the larger end of' the rear passage communicating with the smaller end of the front passage, the rear passage having' a peripheral inlet and the front passage having an enlarged axial outlet, the casing having therein sound boxes adjacent said passages respectively.

3. A sound amplifier comprising a casing having front and rear convolute tapered sound passages in parallel planes, the larger end of the rear passage communicating With the smaller end of the front passage, the rear passage having a peripheral inlet and the front passage having an enlarged axial outlet, the casing having therein an axial sound box around which the rear passage extends, and a peripheral sound box adjacent the outer Wall of the front passage.

4. A sound amplifier comprising a casing having therein a plurality of sound passages each of which is convolute in form around a common axis, said passages being located in parallel planes `with a partition therebetween, said passages communicating with each other through an opening in said partition, one passage having an inlet at the end opposite said opening and the other passage having an outlet at the end opposite said opening.

5. A sound amplifier comprising a casing having therein a plurality of sound passages each of which is convolute in form around a common axis, said passages being located in parallel planes with a partition therebetween, said passages communicating With each other through an opening in said partion, one passage having an inlet at the end opposite said opening and the other passage having an outlet at the end opposite said opening, said inlet being at the periphery of the casing and said outlet being at the center of the casing.

6. A sound amplifier comprising a circular casing having curved Walls therein forming two convolute passages extending around *the axis yof the casing, said passages having a partition therebetween and occupying parallel planes on oppositesides of said partition and communicating with each other through an opening in said partition, one `passagehaving an inlet at the end opposite said opening and the inner wall ofsaid passage forming a circular sound box atthe axis of the casing, and the other passage having an aiXal outlet at the end opposite said opening. y

7. A sound amplifier comprising a circular casing having' curved walls therein forming two convolute passages extending around the axis of the casing, said passages having a partition therebetween and occupying parallel planes on opposite sides of said partition and communicating with leach other through an opening in said partition, one passage having an inlet at the end opposite said opening and the inner wall of said pas sage forming a circular sound box at the axis of the casing, and the other passage lia-ving an axial outlet at the end vopposite said opening, the casing also having therein a sound boX between its circular wall and the wall of the last named` passage.

8. A sound amplifier comprising a circular casing, a rear wall, a front mouthpiece,

a cross partition spaced between said walll and mouthpiece, forming front and rear chambers, and convolute walls in each chamber, between the rear wall and the partition and the mouthpiece and the partition, respectively, `forming rear and front convolute passages communicating with each other through. an opening in said partition, the rear passage having a peripheral inlet, and

the front passage having a central outlet to said'mouthpiece.`

9. A sound amplifier comprising a casing having tapered therein a passa-ge gradually expanding in size from a peripheral inletto a central outlet, said passagey being. in the form of `two adjacent spirals in parallel planes, with a partition'between having an opening yconnecting the spirals.

l0. A sound amplifier comprising a casingA having tapered therein a passage gradually expanding in size rroin a peripheral inlet'k to a central outlet, said passage being inthe form of two adjacent spirals iii parallel GUSTAVE C. VVILHELMI. 

